title: [Genetic study of the mechanism of tandem duplication formation in conjugational crosses in Escherichia coli K-12].
abstract: The formation of heterozygous tandem duplications of the deo operon was studied in conjugational matings HfrH deoA deoB::Tn5 thyA x HfrH deoC deoD thyA. When the HfrH deoC deoD thr::Tn9 car::Tn10 thyA donor strain was used, the thr::Tn9 and car::Tn10 transposon insertions linked to the deo operon were integrated into some duplications. Duplications carrying the recipient thr+ and car+ alleles in the duplicated state were not found among duplications that did not include the thr::Tn9 and car::Tn10 donor markers. These data indicate that heterozygous deo operon duplications are primarily formed directly during the recombinational interaction between chromosomes in the merozygote, but not on the basis of preexisting sister duplications in the recipient strain. Thus, genetic recombination occurring during the process of conjugation in E. coli induces both symmetrical and unequal crossing over. Nevertheless, when the HfrH deoA deoB::Tn5 thr::Tn9 car::Tn10 thyA strain was used as a recipient, a deo operon duplication containing thr::Tn9 and car::Tn10 markers was found in the homozygous state. Consequently, some heterozygous duplications can also be formed on the basis of preexisting sister duplications.
authors.affiliation: State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, Russia.
authors.forename: V V
authors.initials: VV
authors.lastname: Sukhodolets
mesh_terms: D003227:Conjugation, Genetic; D003433:Crosses, Genetic; D004926:Escherichia coli / Q000235:genetics*; D005819:Genetic Markers; D006579:Heterozygote; D009876:Operon; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D005819:Genetic Markers
vernacular_title: Geneticheskoe izuchenie mekhanizma obrazovaniia tandemynkh duplikatsiĭ v kon'iugatsionnykh skreshchivaniiakh u Escherichia coli K-12.